Potato production requires high phosphorus (P) application with potential negative environmental or nutritional consequences for potato as well as for subsequent crops. Impacts of high available P on yield and plant nutrition of species in potato cropping rotations are inadequately understood, and could result in antagonistic interactions with cationic micronutrients such as zinc (Zn) and manganese (Mn). Three hydroponic experiments were conducted with Russet Burbank potato to elucidate P and Zn relationships and associated interactions with other nutrients. In the first experiment, P solution concentration was constant at 256 µM while Zn concentration varied: 0.1, 2, 6, 18, 54, 162 and 456 µM Zn. In the second, Zn solution concentration was constant at 6 µM while P concentration varied: 32, 64, 128, 256, 512, 1024 and 2048 µM P. In the third, three levels of P and Zn varied in all possible combinations: 32, 128 and 1024 µM P and 0.1, 54 and 486 µM Zn. As expected, Zn increased in all plant parts with increasing old shoots while root P increased. This suggests a P-Zn complex formation in roots preventing movement of P to the shoots of plants under high Zn. This was confirmed under variable P and Zn. Contrary to expectations, a direct impact of increased solution P on Zn uptake or distribution in potato was not observed except at 486 µM Zn in the third experiment. Increased solution P at low Zn levels resulted in a steep increase of P in new and old shoot growth and an accumulation of Mn in potato roots—factors that might indirectly impact Zn nutrition in potato. Although high P levels in potato did not directly reduce Zn content or cause Zn deficiency, excessive P accumulation with insufficient Zn may reduce the activity of Zn by interacting with other micronutrients such as Mn.



College and Department

Life Sciences; Plant and Wildlife Sciences



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potato, phosphorus, zinc, manganese, chelator-buffered, hydroponics, nutrient, deficient, sufficient, toxic, excessive